The present invention relates generally to a multi-function loading and recovery apparatus. More particularly, it relates to an improved loading and recovery apparatus capable of multiple uses, such as use with both "inside" and "outside" rail containers, and that is easy and efficient to operate in a wide variety of loading, unloading, dumping and recovery applications.
There are a variety of known pallet or container loading devices which have the ability to serve a dumping function. However, these known devices suffer from a number of disadvantages because of their design and construction. Generally, the known devices have complicated arm or boom assemblies necessary to achieve their designated functions. And because of their complicated arm or boom assemblies, the known devices are higher priced, require increased maintenance, require high pressure hydraulic systems to accommodate extreme load weights, and are more difficult to operate. Further, while such conventional devices may also utilize a tiltable frame, these devices typically require a distinct third member, such as metal hooks, to connect the arm or boom assembly to the tiltable frame, in order to lift the tiltable frame.
Another disadvantage in prior art loading devices is the requirement that the load, such as a pallet, to be recovered or loaded must be of a length longer than the hoist itself. This requirement is a severe limitation on the use of the loading device when the precise sized pallet or load is not available or practical. Therefore, it is also desirable to have a loading or recovery device that can accommodate a wide range of loads and pallets and still be able to operate in a dumping mode.
U.S. Pat. No. 5,290,138 ("the '138 patent"), owned by the same assignee as the present invention, and hereby incorporated by reference into this disclosure, describes an improved loading and recovery apparatus which solves the problems mentioned above. This apparatus includes an L-arm which can both retract or extend, and which can also be locked to a tiltable frame to permit rotation of the arm and frame structure, as one unified piece, while the L-Arm is in a partially retracted or fully extended position. This gives the apparatus greater flexibility, and permits it to be used with containers having less narrowly constrained lengths.
While the device disclosed in the '138 patent has proven to be successful, there are certain disadvantages still associated with it, and room for further improvements, as disclosed here. For example, there is still a need for a loading and recovery apparatus which can recover and dump both "inside" and "outside" container rails. "Outside"container rail dimensions are typically 361/2 inches ID and 40 inches OD, while "inside" rail dimensions are typically 291/2 inches ID and 331/2 inches. These inner diameter rail dimensions are current industry standards (with an industry standard 1/2 inch gap to accommodate manufacturing tolerances). The outer diameter rail dimensions may be wider. Most of the roll-off containers in existence are "outside rail" types. All known hook lifts can dump only "outside rail" containers. Thus, there is a need for a hook lift that can recover and dump both inside and outside rail containers.
There is also a need for a loading and recovery apparatus with a bumper which can serve as a rearward extension of the vehicle chassis, yet which is collapsible to avoid acting as an obstruction during tilting and dumping. Thus, while the industry standard tilt frame length is about 18 feet, the standard container length is 22 feet, and some customers require the handling and dumping of containers up to 24 feet long. Applicable laws permit a two foot overhang throughout the U.S. and, in some cases, four feet, while a six foot overhang is not permitted. To avoid the expense of a longer chassis, while maintaining the operational advantage of a more maneuverable, shorter chassis a collapsible bumper of between two and four feet is therefore needed. Additionally, the use of such a bumper would avoid both the expense of a longer chassis or a longer hoist, and the problems associated with having to locate bumperettes on the containers or bodies.
Yet another disadvantage associated with known loading and recovery vehicles is the use of steel slide pads to hold the container or body rails in place during loading. The steel-steel interaction of the slide pads and the container rails ensures that the pads will wear. Further, even if a wear pad is bolted to the steel pad, the wear pads will still have to be periodically replaced. Also, if the container is not exactly at the right height when pulled up by the hook, the wear pads can be ripped out by the container rails.
A further disadvantage of prior art devices is their instability during all loading and dumping cycles. While the twin, chassis-mounted outboard cylinders disclosed in the '138 patent were a significant improvement in this regard, there is always a need for increased stability and safety.
It would also be advantageous to provide a rear stabilizer which permits heavier hoist loading, while being adaptable for use on both hard (concrete or asphalt) and soft (dirt, mud or sand) terrain.
It would also be advantageous to provide a stabilizer which permits the front end of the truck chassis to remain on the ground during the loading of heavy loads, or during the loading of pallets or containers which are excessively short, or unevenly loaded (i.e., that have more weight to the front than to the rear). This would not only increase the safety of the combined chassis and hoist, but would also permit safe loading in instances where the hoist would otherwise not be capable of picking up the load.
Further, it would be advantageous to locate the hinge point of the tipping frame and the lift cylinders so as to optimize both dumping and lifting capacity, while permitting both a dump angle of over 60.degree. and the use of four or five rear axles. This last feature allows the vehicle to carry more legal weight, since state weight regulations are tied to the number of axles.
Yet another advantage would be the provision of a lifting and recovery vehicle which combines the following features within the physical envelope defined at the rear of the chassis frame, while being in non-interfering obstruction with portions of the vehicle such as the chassis differential, the axles, the brake chambers, and suspension parts, or the approach angle of the container body during loading: a rear hydraulic stabilizer, a rear hydraulic winch, a pintle hook, and a collapsible bumper.
Finally, it would be preferable to also retain all of the advantages and flexibility provided by the loading and recovery apparatus disclosed in the '138 patent.